BACKGROUND: Collective efficacy has been associated with many health benefits at the neighborhood level. Therefore, understanding why some communities have greater collective efficacy than others is important from a public health perspective. This study examined the relationship between gentrification and collective efficacy, in Montreal Canada.METHODS: A gentrification index was created using tract level median household income, proportion of the population with a bachelor's degree, average rent, proportion of the population with low income, and proportion of the population aged 30-44. Multilevel linear regression analyses were conducted to measure the association between gentrification and individual level collective efficacy.RESULTS: Gentrification was positively associated with collective efficacy. Gentrifiers (individuals moving into gentrifying neighborhoods) had higher collective efficacy than individuals that lived in a neighborhood that did not gentrify. Perceptions of collective efficacy of the original residents of gentrifying neighborhoods were not significantly different from the perceptions of neighborhood collective efficacy of gentrifiers.CONCLUSIONS: Our results indicate that gentrification was positively associated with perceived collective efficacy. This implies that gentrification could have beneficial health effects for individuals living in gentrifying neighborhoods.